David: I live west of you about 300 miles. I fly a C-150/150 and have flown over your mountains a number of times. Usually loaded with myself and the wife along with personal gear and camping gear on the way to the fly in at clinton Iowa. Also I have aux tanks and when I leave home headed East I start out with 50 gals of gas.
I have no problem with flying over your mountains as well as those in my area. My field elev is 5172 asl.
whether or not the 150/150 would serve your needs I can't say but it would be something to look into for you I think.
You have one of our members just north of you. David Rowland up in Erie, Colorado. I am sure he could give you some real good info on the capabilities of the 150/150 since that is what he flies.
Dale Larsen

If over 60 and you wake up in the morning and nothing hurts.....................your dead.
[Linked Image from visitedstatesmap.com]
[Linked Image from visitedstatesmap.com]